私が着いたとき、コンサートはほとんど終わりだった。

The concert was all but over when I arrived.

私(わたし)が着(つ)いたとき、コンサートはほとんど終(お)わりだった。

Watashi ga tsuita toki, konsa-to wa hotondo owari datta.

私 (わたし、わたくし)

I; me; private affairs; personal matter; secrecy; selfishness

が (が)

indicates sentence subject (occasionally object); indicates possessive (esp. in literary expressions); but; however; still; and

着く (つく)

to arrive at; to reach; to sit on; to sit at (e.g. the table)

とき (とき)

regular (stops at every station) Jouetsu-line Shinkansen

コンサート (コンサート)

concert

は (は)

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

殆ど (ほとんど)

mostly; nearly; practically; well-nigh; almost invariably; all but; just about; almost

終わる (おわる)

to finish; to end; to close

だ (だ)

be; is; indicates past or completed action; indicates light imperative

Readings: シ、わたくし、わたし

Meanings: private, I, me

Readings: チャク、ジャク、き.る、 -ぎ、き.せる、 -き.せ、つ.く、つ.ける

Meanings: don, arrive, wear, counter for suits of clothing

Readings: シュウ、お.わる、 -お.わる、おわ.る、お.える、つい、つい.に

Meanings: end, finish